The present invention relates to the production of monoclonal antibodies; and, in particular, to hybrid cell lines capable of continuously producing monoclonal antibodies directed against Treponema bacterial pathogens.
In recent years, the capability to produce monoclonal antibodies specific for the immunogenic determinants of bacterial cells and toxins has provided a new vista of diagnostic and immunotherapeutic agents.
The bacterial genus Treponema is associated with a variety of pathogenic diseases. Of particular significance, Treponema pallidum is a sexually transmitted bacterial pathogen of man responsibe for syphilis. Very little is known about T. pallidum, despite decades of strenuous efforts to understand this organism. The gross lack of information stems primarily from the fact that T. pallidum is one of the very few bacterial pathogens for man that cannot be grown in vitro like other human pathogens. Consequently, researchers attempting to elucidate the nature of the organism and the disease it produces have been confined to cultivating T. pallidum in the testicles of laboratory rabbits.
Untreated syphilis in man is a severe, chronic, and very complex disease that can often be extremely difficult to diagnose. Limitations with current diagnostic tools and the absence of a vaccine have allowed syphilis to flourish at the estimated frequency of approximately 350,000 cases per year in the United States alone, even with the availability of effective penicillin treatment.
Moreover, there are other treponemal diseases which perhaps have a more worldwide impact with respect to morbidity and mortality. Briefly, the treponemes that cause yaws, pinta, and bejel are treponemes morphologically and serologically indistinguishable from T. pallidum. These diseases are very serious worldwide, especially in the socalled third world countries. These diseases are believed to be transmitted through normal person-to-person contact, as opposed to T. pallidum, which is a sexually transmitted agent. As a result these particular diseases are highly contagious and devastating to large populations thereby eluding effective control.
Many attempts at vaccine development over past decades using whole cells, extracts, or adjuvant preparations of T. pallidum or other non-pathogenic treponemes have failed. One study reported the successful vaccination of rabbits with T. pallidum (Nichols) attenuated by .gamma.-irradiation. There are several major drawbacks to this approach as a potential immunization scheme for humans. These include the impracticality of preparing massive amounts of freshly isolated and freshly irradiated treponemes, as well as the dangers associated with hypersensitivity reactions by the recipient to contaminating rabbit proteins present in treponemal suspensions.
Syphilis and other related pathogenic treponemal disease research continues to lag far behind other areas of bacterial infectious disease. In particular, the complexity of the humoral response to T. pallidum infection and the inability to obtain large amounts of T. pallidum cells for subsequent fractionation of constituent antigens have severely hampered identification of the specific immunogens of T. pallidum that are responsible for eliciting protective immunity in rabbits and man. The specific T. pallidum immunogens that remain unidentified and uncharacterized may hold the key to immunological approaches for the control of syphilis.
The somatic cell fusion of plasmacytoma cell lines with treponemal-sensitized spleen or lymph node cells to produce monoclonal antibodies specific for a treponemal species determinant provides a new and innovative way to circumvent major obstacles of the past. Once successfully carried out, a virtually limitless supply of monospecific antibodies for Treponema pallidum antigens will be readily available at all times. These monospecific antibodies could then be used to analyze the antigenic components of the Treponema immunogens. The isolation and characterization of specific Treponema immunogens through the use of the new hybridoma cell fusion technology may provide the materials and insights needed to understand the pathogenesis and immunological control of syphilis, yaws, pinta, and bejel through vaccine development.
The invention seeks to develop continuous hybrid cell lines which produce monoclonal antibody directed against treponemal antigens. Selected cell lines are capable of continuously producing a set of monospecific antibodies that are identical with respect to combining site specificity to a single antigenic determinant exhibited by a treponemal bacteria.